Updated: 27 Jan 2012

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Introduction

We tested 8 electric waterblasters priced from $132 to $944, plus a single petrol-powered model costing $599.

You need the right waterblaster for the job. A smaller machine is fine for cleaning a small patio or path. But for large areas – like preparing a roof for painting – you need a combination of high pressure and a good water flow to do the job effectively.

Our test was of a mix of models: from the serious end of DIY through to lighter models for occasional work.

Models we tested

This report contains test results and recommendations for the following water blasters:

Checklist

If you're thinking about getting a waterblaster (also called a high-pressure cleaner), here's what to consider.

Cleaning power

You can use waterblasters for a variety of jobs – to spruce up paths, clean garden furniture, and more.

However, if you have a big job you want to get done quickly we suggest you hire a heavy-duty industrial machine. This will have a higher combination of pressure and flow rate, which translates into faster cleaner.

Don't waterblast stucco-type houses

Waterblasting claddings made from fibre-cement sheet or stucco is a big no-no. That's because the high-pressure water can penetrate cladding (or any cracks in its surface). And once it's in, the water can't get out. This warning especially applies to "monolithic clad" houses built from the early 1990s up till around 2003.

Be careful with other claddings too

Waterblasting weatherboard, brick, concrete block or steel ("galvanised iron") claddings is acceptable – as long as the nozzle is not brought too close to the surface (less than 500mm) and the spray is not directed closely around door openings, window frames and other openings in the cladding.

And timber decks

The nozzle should not be brought closer than around 300mm to the timber deck surface. If held too close, the water jet can penetrate and damage the timber – reducing the life of the deck.

Jet types

• Rotary: Produce a pulsating and rotating cone of water. They work best on large areas of heavily soiled surfaces like paving, driveways and other surfaces that are not easily damaged by the high-pressure water.
• Fan: Produce a flat fan-like spray of water. Useful for cleaning painted surfaces like sides of houses, roofs and vehicles. The spray is not as aggressive as that produced by a rotary jet, but caution is needed with painted surfaces because they can be damaged if the spray is held too close.
• Needle or point: Produce a very concentrated pencil jet. Used for small areas of difficult-to-remove soiling on surfaces that are not likely to be damaged by the high-pressure water. They need to be used with caution – the concentrated jet can damage wood and other less robust surfaces.

Ease of use

Look for a model with spray settings that are easy to adjust. Some require you to let go of the trigger and grasp the lance in the middle, which can be tricky to do.

If possible, test a model out to ensure it's not too heavy for you (models range in weight from 8 to 15 kilograms). Models with wheels and a well-designed handle make moving around easy. Make sure the handle is long enough to use easily.

Rotary start/stop switches on the side are much easier to access than recessed rear switches.

Detergent attachment

Many models carry this handy feature, which dispenses detergent in your water spray, for easy window and surfaces cleaning.

Storage features

A lance-holder lets you stow the lance on the machine while not in use. Likewise, a hose storage hook is handy for keeping your hose neatly stored.

Waterblaster safety

Every year hundreds of New Zealanders require medical attention for injuries incurred while using their waterblasters. The most common types of injuries include back injuries, falls, eye injuries and burns.

ACC has provided these tips to help you keep safe while using your waterblaster:

• Pay attention to where the nozzle is pointing. High pressure water can cause serious injury if it is directed at people or animals.
• Ensure you wear sturdy non-slip footwear, wrap-around safety glasses, hearing protection and stout gloves.
• Be aware of slippery surfaces, especially when carrying heavy equipment that may affect your balance.
• Take care when you move the waterblaster to ensure you don’t block or restrict your work area. Try to keep the work area clutter-free, so that if you do slip and fall, you won’t land heavily or awkwardly on equipment or other obstructions.
• If your waterblaster has a two-stroke motor, take care to avoid its exhaust which can cause serious burns.
• If possible avoid using a waterblaster while on a ladder or the roof. A roof cleaning accessory kit lets you clean the roof while staying on the ground. Other accessories are available to help clean gutters and other hard to reach locations.
• Waterblasting on the roof should be done by a professional who knows how to correctly use a full harness that is fixed to a properly installed anchor bracket.
• If working from a ladder, make sure it is securely positioned and fixed in place so that it can't fall sideways. Maintain 3 points of contact on the ladder at all times (for example, both feet and a hand) and only use the handpiece of the waterblaster from the ladder – don’t attempt to position the waterblaster on the ladder. Ensure you have the right ladder for the job so you don’t have to work from the top 3 rungs.

For more information about DIY and ladder safety go to www.acc.co.nz/preventing-injuries.

More safety advice

• Electrical faults can develop in any appliance over time. So when you're using outdoor electrical equipment you must always have a residual current device (RCD) plugged in between the extension cord and the mains socket. The only possible exception is if you know your new switchboard has built-in RCDs.
• Place the waterblaster unit where it won't get wet. Don't clean a waterblaster with its own high pressure water jet. Wipe it down with a cloth. 
• Watch out for damage to your property. Waterblasters, particularly those using a needle jet, can damage soft surfaces like wood and asphalt. Test on a small area first. Pull the lance back, to ease the force of the blast. See the Checklist for more information.

Extension cords

Domestic waterblasters consume around 1700W when blasting. And almost always they'll be connected to the mains by a long extension cord. That cord has to carry over 7 amps of electrical current – so use an extension cord that is rated to 10 amps and is rated for outdoor use.